Six senators are vowing to work across party lines to head off stiff automatic budgets cuts set to take effect in January.

“We are committed to working together to help forge a balanced, bipartisan deficit reduction package to avoid damage to our national security, important domestic priorities, and our economy,” Sens. Carl Levin, D-Mich., John McCain, R-Ariz. and four other lawmakers wrote in a Sept. 21 letter to Senate leaders. “All ideas should be put on the table and considered.”

The letter was made public this week.

The cuts — formally known as sequestration — are required under last year’s Budget Control Act unless lawmakers and the Obama administration agree on a roadmap to reduce future projected budget deficits by $1.2 trillion through 2021.

For fiscal 2013, the sequestration reductions would amount to a $109 billion hit to military and domestic discretionary programs, according to a recent White House analysis based on this year’s spending levels. In their letter, the lawmakers underscored the potentially “devastating” impact of the cuts to the Defense Department and agencies such as the National Institutes of Health and the Centers for Disease Control and Prevention.

A deal has so far been out of reach, however, mainly because Democrats and Republicans are fiercely divided on whether to complement spending cuts with new tax revenue. With Congress now on break for the next month-and-a-half, no action is expected until a lame-duck session scheduled to begin Nov. 13.

In their letter, the group urged Senate leaders to move ahead before then with any needed reviews by the Congressional Budget Office and Joint Committee on Taxation so bipartisan proposals can be ready for congressional evaluation.